From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 992096B0010 for ; Fri, 20 Jul 2018 04:38:56 -0400 (EDT) Received: by mail-pg1-f199.google.com with SMTP id o16-v6so5506180pgv.21 for ; Fri, 20 Jul 2018 01:38:56 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTPS id f59-v6si1228127plf.500.2018.07.20.01.38.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 20 Jul 2018 01:38:55 -0700 (PDT) Subject: Re: [PATCH V2 0/4] Fix kvm misconceives NVDIMM pages as reserved mmio References: <25569674-2d8f-8b54-4ba7-478b57067325@redhat.com> From: "Zhang,Yi" Message-ID: <3e822509-dc66-0fe8-bad6-d4e4ef9eb528@linux.intel.com> Date: Sat, 21 Jul 2018 00:24:41 +0800 MIME-Version: 1.0 In-Reply-To: <25569674-2d8f-8b54-4ba7-478b57067325@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com, jack@suse.cz, hch@lst.de, yu.c.zhang@intel.com, dave.jiang@intel.com Cc: linux-mm@kvack.org, rkrcmar@redhat.com, yi.z.zhang@intel.com Thanks Paolo, let's wait Jan&Dan 's comments. Thank you, Paolo. Regards Yi On 2018a1'07ae??20ae?JPY 16:32, Paolo Bonzini wrote: > On 20/07/2018 16:11, Zhang,Yi wrote: >> Added Jiang,Dave, >> >> Ping for further review, comments. > I need an Acked-by from the MM people to merge this. Jan, Dan? > > Paolo > >> Thanks All >> >> Regards >> Yi. >> >> >> On 2018a1'07ae??11ae?JPY 01:01, Zhang Yi wrote: >>> For device specific memory space, when we move these area of pfn to >>> memory zone, we will set the page reserved flag at that time, some of >>> these reserved for device mmio, and some of these are not, such as >>> NVDIMM pmem. >>> >>> Now, we map these dev_dax or fs_dax pages to kvm for DIMM/NVDIMM >>> backend, since these pages are reserved. the check of >>> kvm_is_reserved_pfn() misconceives those pages as MMIO. Therefor, we >>> introduce 2 page map types, MEMORY_DEVICE_FS_DAX/MEMORY_DEVICE_DEV_DAX, >>> to indentify these pages are from NVDIMM pmem. and let kvm treat these >>> as normal pages. >>> >>> Without this patch, Many operations will be missed due to this >>> mistreatment to pmem pages. For example, a page may not have chance to >>> be unpinned for KVM guest(in kvm_release_pfn_clean); not able to be >>> marked as dirty/accessed(in kvm_set_pfn_dirty/accessed) etc. >>> >>> V1: >>> https://lkml.org/lkml/2018/7/4/91 >>> >>> V2: >>> *Add documentation for MEMORY_DEVICE_DEV_DAX memory type in comment block >>> *Add is_dax_page() in mm.h to differentiate the pages is from DAX device. >>> *Remove the function kvm_is_nd_pfn(). >>> >>> Zhang Yi (4): >>> kvm: remove redundant reserved page check >>> mm: introduce memory type MEMORY_DEVICE_DEV_DAX >>> mm: add a function to differentiate the pages is from DAX device >>> memory >>> kvm: add a check if pfn is from NVDIMM pmem. >>> >>> drivers/dax/pmem.c | 1 + >>> include/linux/memremap.h | 9 +++++++++ >>> include/linux/mm.h | 12 ++++++++++++ >>> virt/kvm/kvm_main.c | 16 ++++++++-------- >>> 4 files changed, 30 insertions(+), 8 deletions(-) >>> >>